Improvement in pulley



T. A. WESTON.

Pulley.

Patented Aug. 6, 1867.,

N, PiTERS. Phalo-Likhogmpmn wasnin wmuc UNITED STATES PATENT OFFICE.

THOMAS ALDRIDGE WESTON, OF BIRMINGHAM, ENGLAND.

IMPROVEMENT IN PULLEY.

Specification forming part of Letters Patent No. 67,470, dated August 6, 1867.

be applied, consists of the following parts, in

combination with each other, namely:

First, two chain-wheelsthat is, wheels havin g their peripheries formed to engage a gear with the links of a chain-the said wheels being of different diameters, and cast or otherwise joined together, thereby making a double chain-wheel, under which designation this part is hereinafter referred to.

Second, an endless chain applied to the double chain-wheel so as to form two depending loops, thus, (the larger diameter of the double chain-wheel is marked a in Figure 1, and the smaller diameter of the said wheel is marked 1):) The course of the chain may be traced by commencing on that side of the part a nearest the observer, from which side the chain descends, forming a loop, a, and, ascending to the farthest side of the part 1), passes over the said part I) and descends, forming another loop, (I, and, ascending to the distant side of the part c, passes over the same to the point at which its course was commenced to be traced.

Third, to prevent the chain being thrown off the double chain-wheel, or out of gear with it, the projections e e are formed on or attached to the pulley-frame, Fig. 2 or, to attain the same end, the double roller shown in section in Fig. 8 may be used, the axis of the said roller being mounted in the upper part of the frame, Fig. 2, which, in this case, is without the projections e e.

The action of my improved pulley is as follows: WVhen the double chain-wheel, Fig. 1, is rotated in the direction indicated by the arrows, the loop 0 will have taken from it at; each revolution of the said wheel a length of chain equal to the larger circumference, a, and at the same time receive a length of chain equal to the lesser circumference, b, of the said wheel. The loop 0 is thus shortened, while the loop d is equally lengthened by receiving a length of chainequal to the circumference of a, and having taken from it a length equal to the circumference of b.

A single block, with book for attachment to any desired object, may be placed in either of the loops 0 d,- but the outer loop, 0, is, for general uses, most convenient.

By rotating the double chain-wheel in an opposite direction to that indicated by the arrows, the motion of the loops is reversed, the loop 0 falling while the loop (I rises.

to the wheel may be adopted, to suit the kind of chain used; but, for the common chain, the conformation of wheel shown in Figs. 3, 4, and 5 answers well. I The apparatus can be actuated by pulling the chain; and when the double chain-wheel and its shaft are attached to each other, motion may be given to the said wheel and shaft by a winch-handle, ratchet-lever, or any other contrivance used for giving motion to a shaft. VVheu required, several sets of the improved pulleys may be placed upon and actuated by the same shaft.

single block in each loop, one of which would fall when the other was rising, and, by alternating the rotation of the double chain-wheel in contrary directions, an alternate up and down motion will be given to each single block.

Fig. 1 shows the mode of applying the endless chain to the double chain-wheel, the said chain-wheel being shown in perspective. Fig. 2 represents, in front elevation, a pulleyblock frame for the double chain-wheel, Fig. 1, the said frame having projections c e to keep the chain in gear. Figs. 3, 4, and 5 represent the said double chain-wheel in section, edge figures showing the configuration of the wheel for ordinary chain. Figs. 6 and 7 represent, in front elevation and side elevation, respectively, a set of pulley-blocks constructed ac cording to my invention. Fig. 8 represents a section of a double roller used to keep the Any convenient method of gearing the chain In some cases it may be useful to place a view and front view, respectively, the said vention but I claim as my in'vention- Theaforesaid double chain-wheel and endless chain, combiued in the manner described, and represented in the drawing.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

THOMAS ALDRIDGE WESTON.

v Witnesses LYMAN P. PARKINS, J. HYATT. 

